Unusual idle

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Jun 1, 2012 | 09:06 PM

#16

Christof13T

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Joined: Apr 2012

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From: North Georgia

timing?

xtof

Jun 2, 2012 | 06:20 AM

#17

chrislorl

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I highly doubt it. My truck runs great, powerful, and responsive. The idle issue is intermittent and pulsates. If the timing was off it would always be off.

Jun 2, 2012 | 07:25 AM

#18

4EXTRDR

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Sounds like you have a very nice truck chrislorl and you made a valiant effort to fix the small idle lope...my $.02...let it lope

Mine also runs w/ fantastic power and it's been doing this for the last 100K. Who knows...maybe we got lucky and have experimental aggressive cams from the factory

Jun 2, 2012 | 10:24 AM

#19

chrislorl

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It's funny you say that, because when I explain it to someone that knows nothing about Diesel engines and how they run I tell them it feels like a cam lope.

Well I love the truck, it's in great shape. Most of the things I have swapped I figure they were do anyhow and 11 years old and 198K. The injectors and down tubes made a huge difference, feels like new again. But after going through the PCM issue and being broken down, everytime I get that slight hiccup my heart jumps a little.

So this morning I put a new fuel pump and filter in. Guess what!!! No change, same strange hiccup and lope.

The pump looks great on the fuel rail, the bracket is all nice and clean, but that's about it.

Jun 4, 2012 | 07:17 PM

#20

chrislorl

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bump.. anyone have a guess?

Jun 8, 2012 | 05:55 AM

#21

chrislorl

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So yesterday it was raining pretty much all day, when I left work the idle was more consistently rough. Not really a lope but a steady rough idle.
This leads me to believe it may be electrical, maybe the constant moisture has something to do with it????

Jun 8, 2012 | 05:59 AM

#22

4EXTRDR

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Quote:

Check your ICM...I had one where once removed, I could literally here water inside it. Or of you have a buddy w/ one of our trucks...do a quick swap to see if it makes a difference. Your change in the rain is also a CPS sign too. their is also a remote chance your connection to the ECM through the firewall could be leaking....(1) 10mm bolt under the brake booster under the hood to access it....look for moisture.

Jun 13, 2012 | 08:35 PM

#23

chrislorl

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Thanks for the ideas.
IDM, replaced about 60 days ago as part of trying to figure this out.
All leads from the IDM were checked by eye and with a meter, no problems found.
I pulled the wheel well lining out again, checked all harnesses, removed PCM and other body harnesses, checked and cleaned all connections.
My PCM was replaced about 9 months ago, the original failed and would cut out just by tapping on it.
CPS, well there have been gray and Black, I have 4 in boxed and run a old style black one from new stock.